As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOSS OF ALL HEADING INFO ON CAPTAIN'S SIDE DISPLAYS. GROUNDED - YES. DIVERSION TIME 38 MINUTES. #1 IRU LOGGED 34-21009 ENTER HEADING, DFCS FAULT REVIEW LOGGED 5 ADIRU #1 DATA INVALID FAULTS LAST LEG. R/R #1 ADIRU PERB737-800 AMM 34-21-01. SYS OPS CKS NML PER SAME AND DFCS LAND VERIFY 'PASS'.